ďExtraction of phenolic compounds occurs to some extent during mashing, but it is in the sparging that the issue becomes critical (Prechtel, 1964; Scneider, 1997).

He then goes on to mention sparge volume, temperature and pH as factors that should be controlled to limit phenol extraction.

So Yooper was mostly correct. Then again, if ppb can ruin your batch, it would be fun to know the chemistry.

BowWowz, thatís interesting. What kind of filter do you use? Is it granular or solid?

In my experience, a carbon filter is effective at removing chloramine. I have a one micron 10" filter with a flow of almost 1 gallon/minute. The filtered water does not indicate on a total chlorine test strip, which should indicate at Ĺ ppm.

From what Iíve read from Martin and AJ, I should still have some chloramine. Yet I donít see any effect using Campden.

The comment from Fix is in regard to the polyphenols that exist in the husks of the grain. Tannin is a polyphenol. However, this is still related to the issue at hand...the creation of chlorophenols.

The compounds that react with chlorine to create chlorophenol are not only in the grain husk, but they are drawn out into the wort too. With normal mashing, that extraction of tannins and other polyphenols is not objectionable or notable. But it is more than enough to serve as the feedstock to combine with the chlorine to form those chlorophenols that we can taste in the ppb range. So even an all extract wort will react with chlorine infused water to create those unpleasant chlorophenols in beer.

This is not a fermentation phenomena. It is a 'wort creation' phenomena that can occur whether you are mashing or adding extract to water.

The comment from Fix is in regard to the polyphenols that exist in the husks of the grain. Tannin is a polyphenol. However, this is still related to the issue at hand...the creation of chlorophenols.

The compounds that react with chlorine to create chlorophenol are not only in the grain husk, but they are drawn out into the wort too. With normal mashing, that extraction of tannins and other polyphenols is not objectionable or notable. But it is more than enough to serve as the feedstock to combine with the chlorine to form those chlorophenols that we can taste in the ppb range. So even an all extract wort will react with chlorine infused water to create those unpleasant chlorophenols in beer.

This is not a fermentation phenomena. It is a 'wort creation' phenomena that can occur whether you are mashing or adding extract to water.

So chlorine in the mash is bad and will lead to chlorophenols in the beer?

It can and sometimes it does but other times it doesn't and let's limit the discussion to chloramine as chlorine isn't stable enough to make it through to the mash tun. As a general rule if you can't smell chlorine in the water you intend to brew with as it is being poured back and forth between two tumblers then you have eliminated enough of it that clorphenol production is unlikely. But there are always exceptions to rules. To be sure use a test kit (capable of detecting combined chlorine) or use enough metabite that the treated water smells of sulfur dioxide.

So searching for chlorine and chloramine removal brought me to this thread.....

mabrungard;
From the site you linked to I found among much other technical water information I will delve into later..

Quote:

"4.1.3 Metabisulfite (Campden Tablet) addition is effective for chlorine and chloramine removal. The tablets are either potassium metabisulfite or sodium metabisulfite. Both are effective in disinfectant removal. When sodium content in the brewing water is a concern, potassium metabisulfite may be preferred. Moderate potassium content in brewing water generally has less effect on brewing performance or taste. Adding these compounds at a rate of about 9 milligrams per liter (~35 milligrams per gallon or ~1 tablet per 20 gallons) or (~1 tablet per 75 liters) will dechlorinate typical municipal water and leave residual concentrations of about 3 ppm potassium or 2 ppm sodium (depending on the chemical used) and 8 ppm sulfate and 3 ppm chloride. These ion contributions are relatively insignificant and can be ignored in practice. "

This appears to be the optimal method; quickest, most reliable way to remove chlorine and chloramine from my tap water (the only issue I want to deal with at this point)

Yes? or am I missing something?

Next: did I pull the right numbers.. potassium metabisulfite or sodium metabisulfite dosage rate is 35 milligrams per gallon?

As to the source of phenols: they are many. We are mainly concerned here with the ones extracted from the grains. All (or perhaps I should say nearly all just to be safe) plants produce some phenol compounds for a variety of reasons. Even if you are careful in sparging you will extract some phenolic compounds from the grain (example: ferulic acid - the phenolic that we rely on the yeast to turn into clove flavor in wheat beers). I'm sure the chemistry of chlorphenolics is as diverse as the chemistry of phenols and I'm sure some are more potent in flavor than others but one thing I can say is that if there is no chlorine there will be no chlorphenolics of any kind.